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| author |  Jeff King <peff@peff.net> | 2016-06-13 00:36:28 -0400 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2016-06-14 13:57:42 -0700 |
| commit | 905f27b86ac1f50c6870a064c3b5b9d82c97a145 (patch) | |
| tree | fa634994e9cc09c9c326c83d593cf6444e39c80e /Documentation | |
| parent | repack: document --unpack-unreachable option (diff) | |
| download | tgif-905f27b86ac1f50c6870a064c3b5b9d82c97a145.tar.xz | |
repack: add --keep-unreachable option
The usual way to do a full repack (and what is done by
git-gc) is to run "repack -Ad --unpack-unreachable=<when>",
which will loosen any unreachable objects newer than
"<when>", and drop any older ones.
This is a safer alternative to "repack -ad", because
"<when>" becomes a grace period during which we will not
drop any new objects that are about to be referenced.
However, it isn't perfectly safe. It's always possible that
a process is about to reference an old object. Even if that
process were to take care to update the timestamp on the
object, there is no atomicity with a simultaneously running
"repack" process.
So while unlikely, there is a small race wherein we may drop
an object that is in the process of being referenced. If you
do automated repacking on a large number of active
repositories, you may hit it eventually, and the result is a
corrupted repository.
It would be nice to fix that race in the long run, but it's
complicated. In the meantime, there is a much simpler
strategy for automated repository maintenance: do not drop
objects at all. We already have a "--keep-unreachable"
option in pack-objects; we just need to plumb it through
from git-repack.
Note that this _isn't_ plumbed through from git-gc, so at
this point it's strictly a tool for people doing their own
advanced repository maintenance strategy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/git-repack.txt | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/git-repack.txt b/Documentation/git-repack.txt index cde7b4441d..68702eab19 100644 --- a/Documentation/git-repack.txt +++ b/Documentation/git-repack.txt @@ -134,6 +134,12 @@ other objects in that pack they already have locally. the write of any objects that would be immediately pruned by a follow-up `git prune`. +-k:: +--keep-unreachable:: + When used with `-ad`, any unreachable objects from existing + packs will be appended to the end of the packfile instead of + being removed. + Configuration ------------- |